Variable condenser



' May 9, 1944. s KESTER 2,348,392

VARIABLE CONDENSER Filed July 8. 1942 INVENTOR 5 flz-ZMni Z1 ester 8 BYflWJ ATTORN EY Patented May 9, 1944 VARIABLE CONDENSER Arthur S. Kester,Chicago, 111., assignor to The Rauland Corporation, Chicago, Ill., acorporation of Illinois Application July 8, 1942, Serial No. 450,169

2 Claims.

This invention relates to new and useful improvements in variablecondensers.

The object of the present invention to effect certain improvements inthe condenser structure disclosed in my copending application Serial No.425,987, filed January 8, 1942.

I To carry out this object, means are provided to prevent the movementof the condenser plates, and thus the varying of the capacitance, exceptunder the wishful control of the operator and for simplifying themounting of the control or driving shaft.

A preferred embodiment of the invention will now be described withreference to the drawing in which Fig. 1 is a side elevation with partsbroken away;

Fig. 2 is another side elevation partly in section;

Fig. 3 is a section taken along lines 3-3 of Fig. 1;

Fig. 4 is a perspective view of the disc for taking up the end thrust onthe main shaft;

Fig. 5 is a side elevation of the support for one of the bearings of thedriving shaft; and

Fig. 6 is a perspective, with parts broken away, of a bearing of thedriving shaft.

The condenser consists of rotor plates l mounted on a long sleeve 2 andcooperating with stator plates 3 which are fastened by means of screws 4between two opposite strips of insulation, one of which is shown at 5 inFig. 1. One end of strip 5 is fastened by a screw 6 to a shoulder 1(Figs. 1 and 3) of the main frame, which in the structure illustrated isa casting carrying the control elements. The other end of the strip 5 isfastened to an end plate (not shown). The other insulating strip whichis not shown is fastened to a shoulder 8 (Fig. 3) of the main castingand the above mentioned end plate.

A similar stator rotor assembly is provided on the left-hand side of themain casting (Figs. 1 and 2).

The main casting has a front wall 9 and two spaced transverse wings It)and II. The front wall has a central window opening l2. The wings I!)and H have their corners cut-off to form said shoulders I and 8, Thesleeve 2 surrounds and is fastened to the right-hand portion of a shaftis which traverses the whole length of the condenser through openings inthe wings ill and II where it is seated in ball bearings like M (Fig.2).

Between the wings I and II, the shaft l3 carries a gear l hub l6 ofwhich is pinned to .carries also a semi-circular casting la providedwith a number dial or scale and a quadrant i9 rotatably mounted on a hub(Fig. 3) of the casting IS, the latter being fastened to the shaft I: bya set screw. The edge of the quadrant l9 which is visible through thewindow i 2 has a reference line 2| (Fig. 2) cooperating with the scaleon dial it. The position of quadrant l9 and, therefore, of the referenceline 2| is determined by a set screw 22 against which I! is pulled by acoiled spring 23. The set screw projects through an ear 24 of across-piece 25 which is fastened to the wings II) and II of the maincasting by screws 26. One end of spring 231s fastened to quadrant l9 andthe other end to the cross-piece 25 below screw 22.

The shaft l3 and thus the rotors of the condenser and dial it may berotated by turning a knob 21 fastened to one end of a transverse driv-20 ing shaft 28. A dial 29 is integral with knob 28 and serves toindicate the angular displacement of the driving shaft which has a worm30 engaging the teeth of gear [5 against which it is pulled by a coiledspring 3|. The teeth of the worm and gear being wedge-shaped, back-lashis prevented.

One end of spring 3! is attached to asquare bearing 32 on the end ofshaft 28. The bearing 32 is held within two lateral guides 33 (Figs. 3

and 5). The guides are formed in a vertical arm 34 of the cross-piece 25and they are closed at the bottom as shown at 35. The other end ofspring 3| is wrapped around an adjusting screw 36 in thecross-piece 25.The bearing 32 is allowed a limited lateral movement between a shoulder31 and a ring 38 on the shaft.

In order to guard against the rotation of the condenser by a downwardthrust on the projecting end of the shaft or an upward thrust on theknob 21, a screw-threaded stop 39 is provided in the bottom 35 of theguide 33. If the stop 39 were not provided, then the bearing 32 would befree to move far enough to cause the rotation of the main shaft owing tothe torque exerted by worm so on gear 15. The stop can be set forallowing up and down movement of the ends of shaft 28 to any desiredextent.

The spring 3| will lift the back end of the shaft 28 so as to insuregood contact between l5 and 30. The slight bodily displacements of thedriving shaft are made possible by providing a ball shaped bearingsurface 40 thereon, the worm 30 being intermediate the two bearings 40and 32.

Theball 40 engages a cup-shaped seat 4| on a the shaft at H. Thisportion of the shaft i3 sleeve 22. The sleeve is anchored in position bytwo lugs 43 projecting in slots of a retaining plate 44. The plate 44 isfastened to a bushing 45 formed in the main casting and is spaced fromplate 5| by a felt or rubber pad 52. The sleeve 42 houses a coiledspring 48 which presses seat I into contact with ball 40. The curvatureof the seat 4| is such that no torque is apparent when the knob 21 isfree.

The end thrust in the rotor shaft i3 is absorbed by a disc 48 (Figs. 2and 4) on shaft i3 between sleeve 2 and wing II and which together withits supporting rigid washer I8 is fastened to the latter by screws 41.Spring fingers 48 stamped out of disc 46 bear against wing ll adjacentthe outer race of the ball bearing II. A washer II is within the circleformed by spring fingers 48 and prevents the pressing of disc 48 towardsbearing it to such an extent as to distort the spring fingers 48.

The main casting is mounted on a plate II which may be attached to apanel.

What I claim is:

1. In a drive for variable condensers and the like, a main shaft, adriving gear fastened to the shaft, a driving shaft having a wormintermediate its ends engaging said gear, a bearing for one end of saiddriving shaft, 9. guide confining one end of said bearing for movementin one plane, resilient means forcing said bearing in said plane in adirection to press the worm into engagement with the gear, a movablestop limiting the motion assesses c! said bearing in the oppositedirection in said plane, a ball formed on the driving shaft between theworm and its other end, a cup shaped seat for said ball, and a knobfastened to said other end of the shaft for rotating it.

2. In a drive for variable condensers and the like, a frame having twospaced transverse wings, a main shaft projecting through the wings, abearing for the shaft in each wing, a driving gear fastened to the shaftbetween the two Wings, a horizontal transverse shaft between the wingsat right-angles to the main shaft and having a worm intermediate itsends engaging said gear, a bearing for one end of said transverse shaft,a guide having a bottom and side walls between which the bearing ismounted free to move vertically, a coiled spring attached to saidbearing and tending to pull it up vertically and thus the worm intoengagement with the gear, a screwthreaded stop projecting through thebottom of the guide into engagement with said bearing limiting itsdownward movement, a ball formed on the transverse shaft between theworm and its other end, a sleeve on said transverse shaft and having acup-shaped seat for said ball and two positioning lugs, a coiled springwithin said sleeve surrounding the shaft, and a retaining plate fastenedto said frame having notches for said lugs and an opening for thepassage of the transverse shaft.

ARTHUR S. m.

